These studies gather data on pituitary function as it relates to gonadal, thyroid, adrenal, and growth hormone regulation in normal aging men from the Baltimore Longitudinal Study on Aging (BLSA). Recent results have shown that healthy men have no apparent change in growth hormone secretion compared with the decrements of secretory capacity reported for less well selected populations, but subtle alterations in diurnal secretory pattern for ACTH and cortisol, with a decrease in AM/PM cortisol ratio and a trend toward increased pituitary ACTH response to corticotropin releasing factor (CRF). The DHEA secretory response for ACTH is greatly decreased with age, in contrast to the results for cortisol, suggesting independent regulation of cortisol and DHEA secretion.